Method for the two stage filling of flexible pouches

Abstract

The apparatus, for filling a flexible pouch having a bottom end, an opposite top end, and a pair of side edges extending between the bottom and top end, includes a filling station, a supply of compressed purging gas, and a gas purging station. The filling station includes a feeder that dispenses an amount of product into the pouch. The gas purge station is positioned subsequent to the filling station and includes a pair of gas lances. Each of the pair of gas lances have an outlet to discharge the purging gas into the pouch. The pair of gas lances being moveable between an inserted position and a withdrawn position. In the inserted position the pair of gas lances are disposed within the pouch a predetermined distance above the amount of product, and in the withdrawn position the pair of gas lances are provided above the top end of the pouch.

It is claimed: 
     
       1. A method of filling and sealing a flexible pouch comprising the steps of: providing a flexible pouch having a bottom end, an opposite top end, and a pair of side edges extending between said bottom end and said top end, said pouch having an interior accessible through said top end;
 filling said pouch with a first amount of product; 
 primarily purging said interior of said pouch with a compressed purging gas so as to remove residual oxygen remaining after filling said pouch with said first amount of product; 
 filling said pouch with a second amount of product after said primarily purging of said pouch filled with said first amount of product; and 
 secondarily purging said interior of said pouch with said compressed purging gas so as to remove residual oxygen remaining after filling said pouch with said second amount of product. 
 
     
     
       2. The method of  claim 1 , wherein said step of primarily purging said interior of said pouch includes providing a first pair of gas lances reciprocatingly moveable between an inserted position and a withdrawn position, said first pair of gas lances in said inserted position being within said pouch a predetermined distance above said first amount of product, each one of said first pair of gas lances being disposed adjacent and spaced apart from one of said pair of side edges of said pouch, and said first pair of gas lances in said withdrawn position being disposed above a top end of said pouch. 
     
     
       3. The method of  claim 2 , wherein upon movement from said withdrawn position to said inserted position, said first pair of gas lances discharge said compressed purging gas at a first descent pressure, and upon movement from said inserted position to said withdrawn position, said first pair of gas lances discharge said compressed purging gas at a first ascent pressure, said first descent pressure being different than said first ascent pressure. 
     
     
       4. The method of  claim 3 , wherein said first descent pressure is greater than said first ascent pressure. 
     
     
       5. The method of  claim 3 , wherein one of said first descent pressure and said first ascent pressure is a constant pressure and one of said first descent pressure and said first ascent pressure varies with a depth of said first pair of gas lances within said pouch. 
     
     
       6. The method of  claim 3 , wherein said each one of said first pair of gas lances having an outlet at a distal end to discharge said purging gas into said pouch, said first pair of gas lances extend parallel and spaced apart a distance less than a distance between said pair of side edges of said pouch. 
     
     
       7. The method of  claim 2 , wherein the step of filling said pouch with said first amount of product includes stacking the product with a triangular shape so as to provide an apex during said filling of said pouch with said first amount of product,
 wherein each one of said first pair of gas lances in said inserted position being disposed adjacent and spaced apart from one of said pair of side edges of said pouch such that there is a space between each one of said first pair of gas lances to permit accumulation of the product having the apex and in which each one of said first pair of gas lances in said inserted position is disposed between one of said pair of side edges of said pouch and the product, below the apex of the product, without contacting the product. 
 
     
     
       8. The method of  claim 2 , wherein said step of primarily purging said interior of said pouch includes providing tension to each of said pair of side edges adjacent the top end of said pouch to pull the top end of said pouch taut as said first pair of gas lances are moved from said inserted position towards said withdrawn position. 
     
     
       9. The method of  claim 1 , wherein said step of secondarily purging said interior of said pouch includes providing a second pair of gas lances reciprocatingly moveable between an inserted position and a withdrawn position, said second pair of gas lances in said inserted position being within said pouch a predetermined distance above said second amount of product, each one of said second pair of gas lances being disposed adjacent and spaced apart from one of said pair of side edges of said pouch, and said second pair of gas lances in said withdrawn position being disposed above a top end of said pouch. 
     
     
       10. The method of  claim 9 , wherein upon movement from said withdrawn position to said inserted position, said second pair of gas lances discharge said compressed purging gas at a second descent pressure, and upon movement from said inserted position to said withdrawn position, said second pair of gas lances discharge said compressed purging gas at a second ascent pressure, said second descent pressure being different than said second ascent pressure. 
     
     
       11. The method of  claim 10 , wherein said second descent pressure is greater than said second ascent pressure. 
     
     
       12. The method of  claim 10 , wherein one of said second descent pressure and said second ascent pressure is a constant pressure and one of said second descent pressure and said second ascent pressure varies with a depth of said second pair of gas lances within said pouch. 
     
     
       13. The method of  claim 9 , wherein said each one of said second pair of gas lances having an outlet at a distal end to discharge said purging gas into said pouch, said second pair of gas lances extend parallel and spaced apart a distance less than a distance between said pair of side edges of said pouch. 
     
     
       14. The method of  claim 13 , wherein the step of filling said pouch with said second amount of product includes stacking the product with a triangular shape so as to provide a second apex during said filling of said pouch with said second amount of product,
 wherein each one of said second pair of gas lances in said inserted position being disposed adjacent and spaced apart from one of said pair of side edges of said pouch such that there is a space between each one of said second pair of gas lances to permit accumulation of the product having the second apex and in which each one of said second pair of gas lances in said inserted position is disposed between one of said pair of side edges of said pouch and the product, below the second apex of the product, without contacting the product. 
 
     
     
       15. The method of  claim 9 , wherein said step of secondarily purging said interior of said pouch includes providing tension to each of said pair of side edges adjacent the top end of said pouch to pull the top end of said pouch taut as said second pair of gas lances are moved from said inserted position towards said withdrawn position. 
     
     
       16. The method of  claim 15 , wherein said step of primarily purging said interior of said pouch includes providing a first pair of gas lances reciprocatingly moveable between an inserted position and a withdrawn position, said first pair of gas lances in said inserted position being within said pouch a predetermined distance above said first amount of product, each one of said first pair of gas lances being disposed adjacent and spaced apart from one of said pair of side edges of said pouch, and said first pair of gas lances in said withdrawn position being disposed above a top end of said pouch,
 wherein said step of primarily purging said interior of said pouch includes providing tension to each of said pair of side edges adjacent the top end of said pouch to pull the top end of said pouch taut as said first pair of gas lances are moved from said inserted position towards said withdrawn position.